Botón para anular/activar la gravedad

source/ball.cpp

@@ -115,4 +115,10 @@ void Ball::modVel(float vx, float vy)
     this->vy = this->vy + vy;
     onFloor = false;
     stopped = false;
+}
+
+// Cambia la gravedad
+void Ball::switchGravity()
+{
+    g = g == 0.0f ? GRAVITY : 0.0f;
 }

source/ball.h

@@ -34,4 +34,7 @@ public:
 
     // Modifica la velocidad
     void modVel(float vx, float vy);
+
+    // Cambia la gravedad
+    void switchGravity();
 };

source/main.cpp

@@ -61,6 +61,18 @@ void pushUpBalls()
 	}
 }
 
+void switchBallsGravity()
+{
+	for (auto ball : balls)
+	{
+		if (ball)
+		{
+			ball->switchGravity();
+			;
+		}
+	}
+}
+
 void deleteBalls()
 {
 	for (auto ball : balls)
@@ -165,64 +177,81 @@ void checkEvents()
 
 		if (event->type == SDL_KEYDOWN && event->key.repeat == 0)
 		{
-			if (event->key.keysym.sym == SDLK_ESCAPE)
+			switch (event->key.keysym.sym)
+			{
+			case SDLK_ESCAPE:
 			{
 				shouldExit = true;
 				break;
 			}
-			
-			else if (event->key.keysym.sym == SDLK_SPACE)
+
+			case SDLK_SPACE:
 			{
 				pushUpBalls();
 				break;
 			}
 
-			else if (event->key.keysym.sym == SDLK_1)
+			case SDLK_g:
+			{
+				switchBallsGravity();
+				break;
+			}
+
+			case SDLK_1:
 			{
 				index = 0;
 				initBalls(index);
+				break;
 			}
 
-			else if (event->key.keysym.sym == SDLK_2)
+			case SDLK_2:
 			{
 				index = 1;
 				initBalls(index);
+				break;
 			}
 
-			else if (event->key.keysym.sym == SDLK_3)
+			case SDLK_3:
 			{
 				index = 2;
 				initBalls(index);
+				break;
 			}
 
-			else if (event->key.keysym.sym == SDLK_4)
+			case SDLK_4:
 			{
 				index = 3;
 				initBalls(index);
+				break;
 			}
 
-			else if (event->key.keysym.sym == SDLK_5)
+			case SDLK_5:
 			{
 				index = 4;
 				initBalls(index);
+				break;
 			}
 
-			else if (event->key.keysym.sym == SDLK_6)
+			case SDLK_6:
 			{
 				index = 5;
 				initBalls(index);
+				break;
 			}
 
-			else if (event->key.keysym.sym == SDLK_7)
+			case SDLK_7:
 			{
 				index = 6;
 				initBalls(index);
+				break;
 			}
 
-			else if (event->key.keysym.sym == SDLK_8)
+			case SDLK_8:
 			{
 				index = 7;
 				initBalls(index);
+				break;
+			}
 			}
 		}
 	}